Researchers have halted the progression of leukemia in mice by restoring the enzyme TET2 in hematopoietic stem cells, either by reestablishing its gene expression in transgenic mice or by promoting the protein’s function with high doses of vitamin C. In a small experiment, vitamin C injections also suppressed leukemia progression in immunocompromised mice transplanted with hematopoietic stem cells from two leukemia patients. “If these findings withstand clinical testing, the impact for patients with blood cancers could be significant,” said Eirini Papapetrou, MD, PhD, associate professor of oncological sciences, medicine, hematology, and medical oncology, at the Icahn School of Medicine at Mount Sinai. “These patients have currently limited therapeutic options, particularly the more elderly patients, who cannot tolerate highly toxic treatment, like high-dose chemotherapy or bone marrow transplantation.”